A user is authenticated using a fingerprint of a finger of the user matched to a known fingerprint of the finger of the user. The user places the finger on a surface of a scanning device, which scans the surface of the finger and generates an image or print of the finger. The scanning device generates an image of the surface of the finger at a spatial resolution sufficient to spatially delineate valleys and ridges in the image of a fingerprint.
The scanning device uses an imaging technique for producing the scanned image of the fingerprint, which can include thermal scanning. Thermal scanning uses temperature differences between the scanned ridges and valleys of a finger to generate the fingerprint. The scanning device includes a thermal resolution sufficient to sense the differences between temperatures of the ridges and temperatures of the valleys.
The fingerprint or information extracted from the fingerprint is compared to a previously stored fingerprint or information extracted from a previously generated fingerprint. The stored fingerprint or information extracted from the previously generated fingerprint is known by the authenticator to be of the person requesting authentication. If the comparison indicates a match, then authentication is indicated, otherwise authentication is denied.
Information extracted from a fingerprint image can include minutiae, which indicate the spatial locations of features of the ridges and valleys, such as bifurcations, beginnings and ends of ridges, and the like. Other information extracted from a fingerprint image can include directional fields and singular points. The fingerprint image can be represented by a binary matrix that indicates for each spatial location a presence of a ridge as one binary value or a presence of a valley as the other binary value.